1. Field of the Invention
This invention relates to a recording member for an ink-jet recording method, and more particularly to a member which is excellent in ink-receiving property and sharpness of an image recorded thereon.
2. Description of the Prior Art
The ink-jet recording method is that a recording is carried out by jetting droplets of a recording liquid (ink) generated by various systems for jetting the recording liquid (for example, an electrostatically attractive system, a system which mechanically vibrates and displaces the recording liquid using a piezo-electric device, a system employing pressure generated by foaming the recording liquid by heating or the like) and adhering all or part of the jetted droplets to the recording member such as paper and the like. Also, it is noteworthy that this recording method is characterized by small generation of noise during recording and capability of high speed writing and multi-color writing.
The recording liquid for the ink-jet recording method contains water as a main component, from aspects of safety and recording aptitude, and polyhydric alcohol is added to the recording liquid for preventing clogging of a nozzle and for improving jet stability, in many cases.
The recording member to be used for this ink-jet recording method includes common paper and a member composed of a substrate and a porous ink-absorbing layer formed thereon, which is designated as a ink-jet recording paper. Whereas, higher and extensive characteristics of the recording member are coming to be demanded with improvement of performance and spread of the ink-jet recording device enabling high speed recording or multi-color recording. Thus, for obtaining recorded images of high resolution and high quality, the recording member for the ink-jet recording is required to satisfy the fundamental requisite performances as shown below.
(1) To be as rapid as possible in absorption of the recording liquid to the recording member.
(2) When ink dots are overlapped, the recording member should not allow the recording liquid attached later to flow out into the ink dot previously attached.
(3) The recording member should not allow the droplet of the recording liquid to spread on it to cause the diameter of the ink dot to be larger than required.
(4) The recording member should allow the shape of the ink dot to be approximate true circle, and its circumference to be smooth.
(5) OD (optical density) of the ink dot should be high. Thereby, the recording member does not allow the circumference of the dot to be obscured.
In addition to the requisite performances as described above, the recording member is further required to satisfy the performances as shown below, for obtaining the recorded image of high resolution equaling a color photograph by a multi-color ink-jet recording method.
(6) To be excellent in color-generating property of a coloring component of an ink.
(7) To be especially excellent in fixing property since the same number of the droplets as that of colors of the ink happen to attach to the same spot with overlapping.
(8) To have a glassy surface.
(9) To have the high degree of whiteness.
An image recorded by the ink-jet recording method has been conventionally used chiefly for a surface image observation. However, development of a recording member appropriate to uses other than the surface image observation is coming to be demanded with improvement of performance and spread of the ink-jet recording device.
The uses other than the surface image observation may include those in which the recorded image is projected by means of optical instruments such as a slide, OHP (overhead projector) and the like on a screen, etc. for observation, color separating plate during preparation of positive plate for color printing, CMF (color mosaic filter) for color display of liquid crystal or the like.
While the diffused light of the recorded image is primarily observed when the recorded image is used for the surface image observation, the transmitted light passing through the recorded image is primarily observed in the recording member to be used for these uses (the uses other than the surface image observation). Accordingly, the recording member to be used for these uses is required to be excellent in light transmitting property, preferably, linear transmission factor in addition to the requisite performances of the general recording member for the ink-jet recording as described above. However, it is the real state that the recording member for transmittance observation has never satisfied all these requisite performances.
Also, the method for fixing the recording agent used in most conventional recording members for the surface image observation is such that a porous ink-receiving layer is formed thereon to absorb the recording liquid into the space formed in the layer. Thus, no gloss is observed on the surface of the recording member on account of the porousness. On the other hand, when the ink-receiving layer has a non-porous surface, there are the faults that, when coming into contact with the recorded image, clothes become dirty and the recorded image is impaired, because a non-volatile component such as polyhydric alcohol and the like in an ink remains in the surface of the recording member for hours after the recording was carried out, and the time for drying and fixing the ink is long.